Potamogeton octandrus
Content
Description
Flowers 7-9, with 4(-5) carpels.
Fruits 1.5-2.4 mm, smooth or keeled, with a prominent beak.
Distribution
Africa present, Asia present, Asia-Temperate: Taiwan (Taiwan present), Asia-Tropical: East Himalaya (Sikkim present); India present; Jawa (Jawa present); New Guinea present; Thailand (Thailand present); Vietnam (Vietnam present), Australasia, E Highlands present, Gulf present, Japan present, Madagascar present, S of the Sahara present, Tropical and subtropical parts of the Old World present
Tropical and subtropical parts of the Old World: Asia (Japan, China, Taiwan, India, Sikkim, Thailand, Vietnam), Africa (S of the Sahara), Madagascar, Australia; in Malesia: Java (highland), New Guinea (Gulf, E Highlands Provinces).
Taxonomy
1 Potamogeton octandrus is a morphologically variable species. Special at-tention must be paid to forms without floating leaves which have been confused with P. pusillus. Furthermore, both hybrids with P. pusillus (P. P apertus Miki) and P. oxyphyllus (P. P kamogawaensis Miki) may occur.
2. Closely related is P. cristatus Regel & Maack in Regel, Tent. Fl. Ussur. (1861) 153, which has been reported from Taiwan (Yang in Fl. Taiwan 5, 1978, 28). Potamogeton cristatus cannot be distinguished by vegetative characters. It differs from P. octandrus in the rather short and densely flowered spike, the cristate dorsal margin of the ripe fruit, and the long and slender style.
Citation
Hook.f. 1894: Fl. Brit. India: 566
A.Benn. 1914 – In: Philipp. J. Sc., Bot.: 339
Leach & Osborne 1985: Freshw. Pl. Papua New Guinea: 225
Hagstr. 1916 – In: Kungl. Svenska Vetenskapsakad. Handl.: 131
Backer & Bakh.f. 1968 – In: Fl. Java: 9
Koord. 1911: Exk. Fl. Java: 89
Yang 1978 – In: Fl. Taiwan: 30